The present invention relates to a material handling vehicle of the type wherein the body of the vehicle is driven by a pair of drive wheels located adjacent the rear end thereof and a pair of steering wheels located adjacent the front end. The vehicle has a material handling unit suspended from the rear end of the body.
In vehicles of this type, the center of gravity of the material handling unit is located a substantial distance rearwardly of the transverse axis for the rear drive wheels. Since the weight of the material handling unit closely approximates the weight of the body of the vehicle, which is located forwardly of the rear drive wheels, it has been customary to provide outriggers that extend from the body or the material handling unit at a point rearwardly of the rear drive wheels for the vehicle. These outriggers are utilized to stablize the vehicle during the use of the material handling unit at a construction site. When the outriggers are in their extended positions, the vehicle is essentially supported on the two outriggers adjacent the rear end of the body and the steering wheels adjacent the front end.
In a vehicle of this type, difficulties have been encountered in transporting the vehicle from one construction site to another. It has been found that when the vehicle is being driven at roadway speeds over rough terrain, an oscillating motion of the vehicle about the axle supporting the rear wheels will be developed. It necessarily results from the fact that the weights on opposite sides of the rear axle or axis are substantially equal. This oscillating motion becomes even more severe even over a fairly smooth road when the oscillatory motion hits some harmonic or resonant frequency. When this situation occurs, it many times results in having the front wheels off the ground for a substantial period of time. To dampen this oscillation, it becomes necessary for the operator to slow the machine to a point were the oscillation is stopped. This of course is highly undesirable since it substantially increases the time required for transporting one vehicle from one construction site to another.